package cms.web.action.staff;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

/**
 * 该过滤器的主要作用就是通过spring著名的IoC生成securityMetadataSource。
 * securityMetadataSource相当于本包中自定义的MyInvocationSecurityMetadataSourceService。
 * 该MyInvocationSecurityMetadataSourceService的作用提从数据库提取权限和资源，装配到HashMap中，
 * 供Spring Security使用，用于权限校验。
 *
 */

public class CustomFilterSecurityInterceptor extends AbstractSecurityInterceptor
	implements Filter{
	

	private FilterInvocationSecurityMetadataSource securityMetadataSource;
	
	public void doFilter( ServletRequest request, ServletResponse response, FilterChain chain)
	throws IOException, ServletException{

		FilterInvocation fi = new FilterInvocation( request, response, chain );
		invoke(fi);

	}
	
	public FilterInvocationSecurityMetadataSource getSecurityMetadataSource(){
		return this.securityMetadataSource;
	}
	
	public Class<? extends Object> getSecureObjectClass(){
		return FilterInvocation.class;
	}

	
	public void invoke( FilterInvocation fi ) throws IOException, ServletException{
		InterceptorStatusToken  token = super.beforeInvocation(fi);
		try{
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
		}finally{
			super.afterInvocation(token, null);
		}
		
	}
		
	
	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource(){
		return this.securityMetadataSource;
	}
	
	
	public void setSecurityMetadataSource(FilterInvocationSecurityMetadataSource securityMetadataSource){
		this.securityMetadataSource = securityMetadataSource;
	}
	
	
	public void destroy(){
		
	}
	
	public void init( FilterConfig filterconfig ) throws ServletException{
		
	}
	
	
}
